Envelope with sealing means

ABSTRACT

A sealing strip which is particularly useful for securing two layers of paper together, for example sealing the flap of an envelope, which consists of a paper carrier of low internal strength coated on both sides with a pressure-sensitive adhesive. One or both adhesive surfaces may be protected with a removable strip of paper or plastics material.

United States Patent Sorrell 51 July 11, 1972 [54] ENVELOPE WITH SEALINGMEANS [72] Inventor: Stanley Edward Sonell, Glossop, England [73]Assignee: Sterling Coated Materials Limited,

Cheshire, England [22] Filed: March 9, 1970 211 App1.No.: 17,539

[52] U.S. Cl. ..229/80, 161/167, 161/270, 161/406, 206/56 AA [51 Int.Cl. ..B65d 27/16, B65d 27/30 [58] Field of Search ..229/77, 79, 80, 4 8T, 48 SB, 229/51 WB; 161/167, 406; 206/D1G. 18, 56 AA [56] ReferencesCited UNITED STATES PATENTS 3,070,280 12/1962 Richmond ..229/802,030,135 2/1936 Carpenter ..206/D1G. 18

3,306,521 2/1967 Giacovas .229/48 SB X 3,346,105 10/1967 Nye 161/406 X2,404,337 7/ 1946 Williams ..229/80 X 2,205,956 6/1940 Humphner.....161/406 X 3,001,689 9/1961 Burton 229/51 WB X 2,550,151 4/1951 lknayan..161/406 X 2,914,167 11/1959 Holtz 161/406 X 3,111,449 11/1963 Gold....161/406 X Primary Examiner--Donald F. Norton Attorney-James E.Nilles [57] ABSTRACT A sealing strip which is particularly useful forsecuring two layers of paper together, for example sealing the flap ofan envelope, which consists of a paper carrier of low internal strengthcoated on both sides with a pressure-sensitive adhesive. One or bothadhesive surfaces may be protected with a removable strip of paper orplastics material.

4 Claims, 4 Drawing Figures Fuji 7 INVENTOR:

5. E. SORRELL %aila 577% ENVELOPE WITH SEALING MEANS This inventionconcerns sealing means of the kind (hereinafter termed of the kindreferred to) adapted to form a seal between two layers of paper,particularly though by no means exclusively suitable for sealing certainarticles of stationary such as wage envelopes.

In the manufacture of wage envelopes, it is necessary to provide a meansfor the sealing of same. This can either be a strip of waterremoistenable adhesive, heat activated adhesive, or pressure-sensitiveadhesive, protected before use by means of a strip of release paper, orfilm, or other removable material. The first two adhesive types sufferfrom the disadvantages that they are difficult to apply and that theyneed activation before a seal can be made. The third adhesive, in itsconventional form, suffers from the disadvantage that the bond can bebroken by carefully peeling the flap away, particularly as one layer ofpaper to which it is stuck is often transparent and, in consequence, hasa hard non-fibrous surface.

It is an object of the present invention to provide sealing means of thekind referred to which utilize a pressure-sensitive adhesive and whichovercome at least to some extent the disadvantage aforesaid.

According to the present invention sealing means of the kind referred tocomprises a thin paper carrier of low internal strength which is coatedon both sides with a layer of pressuresensitive adhesive material.

Preferably the paper carrier is supplied in the form of a tape and theadhesive surfaces are protected prior to use by a removable tape orrelease paper, or film or other removable material.

Specific embodiments of the invention will now be described, by way ofexample with reference to the accompanying drawings, in which:

FIGS. 1 to 3 show three different sealing means embodying the inventionand suitable for the sealing of wage envelopes; and

FIG. 4 illustrates the splitting of the carrier paper when the sealingmeans is broken.

Referring to the drawings the sealing means is comprised by a tape ofthin paper having a low internal strength and preferably manufacturedfrom mechanical wood or sulphite pulp, but nevertheless havingcharacteristics which prevent penetration of the adhesive through thebody of the paper.

FIG. 1 illustrates a tape in which a carrier 2 coated withpressure-sensitive adhesive on both sides 1 and 3 is laminated to apaper coated on either side with release coatings 4 and 6. The carrier 2and paper 5 are of the same width. FIG. 2 illustrates a similarconstruction but in which the paper carrier 8 with its adhesive layers 7and 9 is narrower than the release paper 11 coated with the releasecoatings l0 and 12.

FIG. 3 illustrates an example in which the release material I6 is anembossed plastic film, or paper. The paper carrier 14 is coated on bothsides with adhesive 13 and 15.

Referring to FIG. 4 the paper carrier 19 with its adhesive layer 18 isfirst fastened to the flap of, say, a wage envelope 17. When the seal ismade the release paper, which is temporarily attached to the other sideof the carrier by adhesive layer 20 is removed and the adhesive layer isused to bond the tape to the opposite flap of the envelope 2] thusmaking a seal. When an attempt is made to peel the two flaps apart, thecarrier paper, because of its peculiar characteristics, splitslongitudinally, as illustrated. 1

A tape of protective material, capable of releasing from the adhesive,is provided and laminated with the adhesive on one face of the carrierto permit the latter to be wound up into a coil, both adhesive layersthen being juxtaposed with a releasing surface. The release material maybe either paper or plastic film coated on both sides with a coatinghaving non-adhering properties, such as Shellac, suitable combination ofnitro-cellulose and wax, polyethylene or silicone. Another alternativeis an embossed plastic film, wherein the area of contact is reduced tofacilitate removal. The protective, or release material, may be the samewidth as the adhesive coated carrier, but preferably slightly wider toprovide free edges facilitating removal.

In use, for example, a length of the carrier may be secured to the bodyof a wage envelope by means of the adhesive layer on one face thereof ata position adapted to be overlaid by the flap of such envelope, therelease paper being left in position on the outwardly directed adhesivelayer to ensure against premature sealing of the envelope.

When it is desired to seal the envelope, the release paper is peeledfrom the carrier and the flap of the envelope is pressed firmly againstthe then exposed adhesive layer to effect the seal.

The seal is tamperproof, since any attempt to peel the flap open willresult in a splitting of the paper carrier preventing normal re-sealingof the envelope. It will be understood that the internal strength of thepaper carrier must be less than the adhesive forces betweenpressure-sensitive adhesive layers and the paper carrier on the onehand, and between the pressure-sensitive adhesive layer and the body ofthe envelope and envelope flap on the other hand.

The following example illustrates the invention:

A sulphite paper is constructed having the following properties:

was coated on either side 25 gms/sq.m with adhesive prepared inaccordance with the following formulation:

ribbed smoked sheet No. l rubber I00 parts by weight Hydrocarbon ResinI071 50 parts by weight Hydrocarbon Resin 1 I02 50 parts by weightmodified Terpene Resin 2010 30 parts by weight 2 parts by weight 543pans by weight anti-oxidant petroleum spirit The hydrocarbon resins wereof the type supplied by R. H. Cole & Company Limited under the tradename Escores"; the terpene resin was supplied by BX Plastics Limited;the anti-oxidant used was Nonox CNS supplied by [C] Limited.

This was interleaved with a release paper prepared from a 68 gsmVegetable Parchment coated on both sides with a silicone releasecoating, In order to demonstrate the manner in which the constructionworks, tests were carried out using a Keil type tester.

First, the adhesive coated carrier was laminated between two pieces ofMG envelope paper of 73 gsm. The sandwich was then peeled apart at arate of 3 inch/minute. The carrier paper delaminated at a force of 650gms/inch. A similar construction was made using a bleached glassinepaper of 50 gsm substance; in this case the carrier paper delaminated ata force of 350 gms/inch. In both cases, because of the delamination ofthe sandwich, it was impossible to reseal the construction. The sameadhesive was then coated directly on to the MG envelope paper andglassine at a weight of 25 gms. These were laminated to glass and Keiladhesion tests were carried out in the normal manner at a peel rate of 3inch/ minute. The envelope paper delaminated at a force of 1,700gms/inch and the glassine at 1,800 gms/inch. It, therefore, can be seenthat the bond between the envelope paper and the glassine is much higherthan the delamination strength of the carrier paper; also, that thedelamination strength of the envelope paper and the glassine is greaterthan that of the carrier paper, so that always the carrier paper willdelaminate. As hereinbefore mentioned, thin paper having low internalstrength is preferably manufactured from mechanical wood, that is fromwood which has been made mechanically or from sulphite pulp, that isfrom wood which has been reduced to a pump chemically rather thanmechanically.

What is claimed is:

1. In combination a sealing means comprising a thin paper carrier whichis coated on both sides with a layer of pressuresensitive material andan envelope having a flap, said sealing means being secured to the bodyof the envelope in the region adapted to be overlaid by the flap, saidpaper carrier having an internal strength which is less than theadhesive force between a layer of said pressure-sensitive material andsaid paper carrier, between a layer of said pressure-sensitive materialand said body of the envelope, and between a layer of saidpressuresensitive material and said flap.

1. In combination a sealing means comprising a thin paper carrier whichis coated on both sides with a layer of pressuresensitive material andan envelope having a flap, said sealing means being secured to the bodyof the envelope in the region adapted to be overlaid by the flap, saidpaper carrier having an internal strength which is less than theadhesive force between a layer of said pressure-sensitive material andsaid paper carrier, between a layer of said pressure-sensitive materialand said body of the envelope, and between a layer of saidpressure-sensitive material and said flap.
 2. The combination of claim1, in which the outer face of the sealing means is covered by a releasemeans to prevent premature sealing of the envelope.
 3. The combinationof claim 2, in which the release means is of slightly greater width thanthe width of the paper carrier.
 4. The combination of claim 3, in whichthe paper carrier is of low internal strength and is manufactured from asubstance selected from the group consisting of mechanical wood andsulphite pulp.